Question how can i connect 3 fans to a PC with only one fan header?

Karadjgne

Titan
Herald
With 3x 3pin fans, it's not advised putting all 3 on the same header, pushing your luck with maximum amperage used being too close to 1A, if not over. Being voltage controlled, there aren't even any powered hubs or splitters you can use. The best option is to use a fan controller that mounts in a 5¼" optical bay. This at least gives options for separate control of intakes and exhaust.
 

tennis2

Respectable
3 way fan splitter for $7**

**What fans do you have? Make/model. As others have said, 2 fans on a single header is generally considered safe since most fans don't draw more than 0.5A and fan headers are generally rated for 1A. If you go more than 2 per header, you'll need to check. Some fans draw only 0.2A or less. It all depends.

The safe bet would be to use two 2 way fan splitters. One on the sysfan header and one on the CPUfan header.
 
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tennis2

Respectable
Oops. Missed that.
Fan speed max = 800rpm. No LEDs. 0.07A @ 12V. I'd bet a 3-way splitter will work. Even if you put a 3x factor of safety on the amperage for peak.
Not sure what you're getting at with the "can't use 3-pin fan on a 4-pin header" since that's not true.
 

Karadjgne

Titan
Herald
Not all DC fans will spin on 5v-12v (40%-100% duty cycle), many require a minimum of 7v-12v (60%-100% duty cycle), in which case a low or ultra low noise adapter (LNA, ULNA) is used to drop the 12v to 9v or 7v usage (75% or 60% duty cycle)
 

tennis2

Respectable
If you're using that single header for all three fans though...just set the header to 100% duty cycle and you've got 12V. Since the fans' max RPM is only 800rpm, there's no point in running them any less than full speed. They ought to be inaudible.
 

Karadjgne

Titan
Herald
That's just the 2 Arctics. You forget about the cases stock fan. Might not want that at 100%, with the build age many of those older case fans really weren't all that good or quality as they are now and can get unhappily loud.
 

tennis2

Respectable
True (I need to read more closely). If the board supports voltage regulated fans, then you could set it lower, with a bottom limit of not turning the fans (obviously, as you mentioned)
If the OP gets the molex adapter, they'll all run at 100%
 

gabness1

Great
Mar 1, 2019
108
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I had this problem but today I got a hub with 10 3pin connections and 1 3pin for power but it also had 3pin to molex so it is directly to psu. You can get then from amazon very cheaply under 5
 
Arctic silent 120mm are 3pin fans. Most case fans are 3pin fans. You aren't going to be able to use a 4pin PWM splitter on 3x 3pin DC fans from a single 4pin sys_fan header
Why not? I believe most 4 pin headers support 3 pin fans, and I don't see how having a splitter really changes anything.

Those two Artic fans are only rated at 0.07 A at full speed. Should be fine running two of those + your stock case fan off of 1 header. The downside is that you can't control the speeds independently.
 

Karadjgne

Titan
Herald
Sigh.

The 4pin header will accept 3 or 4pin connections. Many 4 pin splitters do not. My guess being that analog DC fans used to have much greater draws, some over 0.5A each, so sticking 3 or 4 analog fans on a 3 or 4way splitter was tantamount to a burned up motherboard and guess who gets the blame.

Those Arctic fans take 4v to start, and run at 0.071A. What's the startup amperage?

Op more than likely has an older case. Got a h110m in it, Gigabyte no less. Think it's really got the full supposed 1A capacity? Try closer to 0.8A. What stock fan? Some old junky 0.5A no name brand cheapo? What's the startup amperage on that? Closer to 0.7A?

It's op's choice, but honestly I'd not push my luck praying that every time he boots up the header doesn't fry with overloaded startup amperage. You might.
 

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